Production solutions, such as water and liquid fertilizers, are generally applied to container grown plants having open root zones (that is, an open top surface and a draining bottom surface). Production solutions may be applied either to the top surface of the open root zone by overhead irrigation or drip irrigation techniques, or to the bottom surface of the root zone by capillary or sub-irrigation techniques.
Precipitation or production solutions applied to top surfaces may dissolve fertilizer placed on top of or incorporated into plant growth media. Surface-applied water flows by gravity through the container, carrying the fertilizer away as leachate before the fertilizer can be used by the plant roots. Accordingly, much fertilizer is wasted.